The present invention generally relates to an intraocular lens (IOL) delivery device used for inserting an IOL into an aphakic mammalian eye that has undergone, for example, a cataract surgery or into a phakic eye in refractive surgery.
Elimination of an opacified crystal lens through an ultrasonic emulsification and implantation of a lens into an eye that has undergone the elimination of a crystal lens are commonly carried out in cataract surgeries. Currently, a soft IOL (such as is disclosed in United States Patent Application Publication No. 2011/0082463) made of a soft material, such as a silicone elastomer or a soft acrylic material, is used; an optical part of the IOL is folded by an IOL lens folder (such as is disclosed in United States Patent Application Publication No. 2009/0270876) insertion device, the IOL in this state is pushed by a plunger to drive the lens out of a nozzle, and insert it into an eye through an incision made to be smaller than the diameter of the optical part.
IOL insertion devices are designed to insert an IOL into an eye through a tiny incision in order to reduce the possibility of a corneal astigmatism or an infection following surgery. To reduce the possibility of a corneal astigmatism or an infection following surgery, it is desirable to minimize the incision used for inserting an IOL into an eye as much as possible. This requirement in turn places additional demands upon the IOL delivery device.
In order to further reduce the size of the incision, it is necessary to fold an IOL into a smaller size to accommodate the miniaturization of the incision. Folding an IOL into a smaller size while attempting to push it through the necessarily small folder increases friction between the lens and folder thereby resulting in increased resistance to advancement of the plunger used to push a lens out of the IOL delivery device and into an eye. The IOL delivery device plunger must therefore be driven with great force, but in a very controlled manner and without a quick surge of stored energy upon release of the IOL into the eye as it exits the folder's delivery tube.
Syringe like, manually driven delivery devices are hard for users to control, particularly when the IOL exits the folder's tube and the large force necessary for delivery drops almost immediately to zero. Upon this transition of force, there exists a real possibility for the user to lose control of the device tip inserted within the miniature incision and cause tearing or injury to the eye. Similarly, manually operated screw based IOL delivery devices tend to deliver lenses very slowly; they can require two hands to operate, and the user motion necessary to operate them results in moving, pulling and pushing of the IOL folder's tube against the miniature incision which again risks tearing the tissue. Many surgeons prefer to have one hand free to help steady the patient's eye during lens implantation. Electrically driven (i.e., U.S. Pat. Nos. 5,354,333; 8,308,736 and 8,808,308), hydraulically controlled (i.e., United States Patent Application Publication No. 2008/0255579 and European Patent No. EP 0937443), high pressure gas driven (i.e., U.S. Pat. No. 8,998,983 and United States Patent Application Publication No. 2015/0282928) and spring driven (European Patent No. 0937443 and United States Patent Application Publication No. 2015/0088149) types of delivery mechanisms have been contemplated and/or introduced into the marketplace. While these forms of delivery devices can free the surgeon's second hand to assist in the procedure, they often suffer the drawbacks of excess weight, poor balance, mechanical complexity and high expense.
Surgeons performing cataract removal and IOL insertion prefer to execute the procedure expeditiously in order to minimize potential to further traumatize the eye. Additionally, many eye clinics schedule successive procedures closely together in order to utilize the surgeon's time most efficiently. Further, additional handling of lenses by clinic personnel risk damaging the IOLs from handling or misloading them into cartridges and IOL folders which could result in complications during their delivery to the patients eye. Makers of IOLs, recognizing this need for efficiency and error proofing have therefore begun providing IOLs prepackaged sterile, in cartridges having the folder already attached (see, for example, United States Patent Application Publication No. 2007/0270881). Others have designed special IOL receiving cartridges to simplify loading of IOLs for the clinician in order to reduce human error. These cartridges and IOL folders may be provided as an integral part of the overall delivery device (shown, for example, in United States Patent Application Publication Nos. 2013/0226193 and 2014/0200589) or in many instances are provided to be retained by special receiving features built into a universal delivery device containing the necessary plunger and drive mechanism to push a lens through the cartridge and folder and into an eye (shown, for example, in U.S. Pat. No. 7,156,854).
Typically, makers of IOLs have developed dedicated cartridges and folders that work best with their lens design. Further, these lens makers have, in many cases, developed bespoke plunger tip geometries (examples are shown in, for example, U.S. Pat. Nos. 6,733,507; 8,114,095; 8,308,736; 8,758,433; and 8,998,983; as well as United States Patent Application Publication Nos. 2008/0086146; 2010/0217273 and 2010/0228261) for the plunger that works best with the features and design of their specific lens, cartridge and folder members.